Bug 8906 - Improve OAI management interface

Bug 8906 - Improve OAI management interface

Revising OAI configuration interface to conform to
existing interface patterns:

- Properly-formatted form rows
- "clone" and "clear" links consistent with other
  forms which use these conventions
- Improved title and breadcrumbs
- Standard save and cancel markup

New to the mappings interface: A "clear" button
to remove or empty the contents of a row. This replaces
the help text about emptying fields.

To test: view, add and edit OAI sets and mappings. Try adding
and removing multiple set descriptions and mappings.

Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>